Air-water combined sand washing active sand filter

Abstract

The utility model discloses a kind of air-water combined sand washing active sand filter, belong to active sand filter technical field of sewage treatment plant.The filter tank is sequentially provided with clean water area, sand bed area and dirty sand area from top to bottom.Washing sand machine is coaxially arranged in the central part of clean water area, and its bottom sand lifting pipe extends to the bottom of dirty sand area, and air-lift pump is arranged at the inlet end;Water disturbance ring pipe is arranged below pump, and water is sprayed upwards.Water distributor is sleeved outside sand lifting pipe in sand bed area, and water is vertically distributed at lower end.Water distributor is provided with flow guide cover below, and multiple air disturbance ring pipes outside cover are communicated by two symmetrical inclined branch pipes, and branch pipe lower end is connected with air inlet main pipe, and nozzle is tangentially inclined upwards along conical surface.Dirty sand area is inverted funnel-shaped conical bucket, and water disturbance ring pipe is arranged on outer periphery;Sand level monitoring rod is arranged in pool, and it is synchronously moved downwards and output signal with sand layer descending.The utility model combines vertical water jet with rotary airflow, destroys sand particle bonding, prevents hardening and bridging, realizes continuous filtration and sand washing, and has low energy consumption and small maintenance.

Description

Technical Field

[0001] This utility model relates to the technical field of activated sand filters in wastewater treatment plants, specifically to an activated sand filter with combined air-water washing. Background Technology

[0002] Activated sand filters are a type of high-efficiency, continuous fluidized bed filtration system widely used in the advanced treatment units of wastewater treatment plants. Their working principle is as follows: wastewater to be filtered enters from the bottom of the filter tank, flows upward through the sand filter bed, and the purified water is discharged from the top overflow weir. The sand particles, having trapped pollutants, slowly sink to the bottom of the tank under gravity, and are then transported to the top sand washer by an air lift pump for cleaning. The cleaned sand particles fall back into the filter bed for recycling.

[0003] The existing activated sand filter technology has the following main problems in actual operation: 1. At the bottom of the sand guide hopper, sand particles are prone to caking due to the accumulation of pollutants, forming "bridging" or "perforation" phenomena, which leads to poor sand particle flow or even blockage, affecting the continuous and stable operation of the entire filter.

[0004] 2. The bottom sludge and sand zone relies solely on gravity to fall naturally. When the pollutants attached to the sand particles are highly viscous, they are very likely to clump and clog at the inlet of the sand lifting zone, resulting in insufficient sand lifting, reduced filter bed thickness, and deterioration of effluent water quality.

[0005] 3. The rate of descent of the filter bed is a key parameter for judging the operating status of the filter bed. However, there is currently a lack of effective real-time monitoring methods, making it impossible to know in a timely manner whether the sand circulation is smooth. Usually, it can only be discovered after severe blockage and excessive effluent quality, resulting in passive operation and maintenance management. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing an air-water combined washing activated sand filter, which aims to effectively prevent sand layer compaction, ensure smooth sand particle circulation, and monitor the sand particle descent speed in real time.

[0007] To achieve the above objectives, this utility model designs an air-water combined sand washing activated sand filter, comprising a tank body. The tank body is arranged from top to bottom as follows: a clear water zone, a sand bed zone, and a sludge zone. A sand washer is installed in the clear water zone, and a sand lifting pipe is connected to the bottom of the sand washer. The inlet end of the sand lifting pipe extends to the bottom of the sludge zone. An air lift pump is installed at the inlet end of the sand lifting pipe. A water disturbance ring pipe is installed below the air lift pump, and a spray nozzle is provided on the water disturbance ring pipe. A water distributor is installed in the sand bed zone, and a flow guide shroud is provided below the water distributor. Multiple air disturbance ring pipes are provided on the outer wall of the flow guide shroud, and air nozzles are provided on the air disturbance ring pipes. A water outlet pipe is provided on the outer wall of the clear water zone.

[0008] Preferably, the water distributor consists of a central riser and a disc-shaped cavity at the bottom. The central riser and the disc-shaped cavity are coaxially sleeved around the outer periphery of the sand-lifting pipe and are not connected to each other. The top of the central riser is connected to a water inlet pipe. The riser is vertically connected to the cavity. Several water distribution pipes are evenly distributed along the circumference of the lower end face of the cavity, and the axis of each water distribution pipe is vertically downward.

[0009] Preferably, the flow guide is a flat-headed truncated cone, with its large end facing down and having a sand return port, and its small end facing up and closed; the sand lifting pipe passes vertically through the center of the small end and is coaxially arranged with the flow guide, forming an annular sand drop channel between the two.

[0010] Preferably, multiple air disturbance rings are surrounded and fixed on the outer conical surface of the shroud. Each ring is symmetrically arranged and airtightly connected by two oblique branch pipes. The air nozzles are inclined upward along the tangential direction of the conical surface and are spaced circumferentially.

[0011] Preferably, the air inlet ends of the two inclined branch pipes are connected to the main air inlet pipe, which is introduced from the side wall of the pool body, and its outer air inlet end is used to connect to the main compressed air pipe of the plant area or the outlet of an independent blower.

[0012] Preferably, the intake manifold is equipped with an air valve.

[0013] Preferably, a water conveying main pipe is connected to the water disturbance ring pipe, a water pump is provided at the inlet end of the water conveying main pipe, and a water conveying valve is provided on the water conveying main pipe.

[0014] Preferably, the upper part of the side wall of the sand washer is provided with a backwash drain pipe, the inlet of which is connected to the clean water area, and the outlet end of which extends out of the outer wall of the tank.

[0015] Preferably, the pool body is equipped with a sand level drop rate monitoring rod, the bottom end of which is inserted into the sand bed area.

[0016] Preferably, the sludge zone is an inverted funnel-shaped cone with its small opening facing downwards to form a sand-lifting port, and its large opening facing upwards to connect to the return port of the guide shroud.

[0017] The beneficial effects of this utility model are: 1. This utility model adds an air disturbance ring pipe at the bottom of the sand guide hopper, and uses compressed air to intermittently disturb the accumulated sand particles, which effectively destroys the adhesion between the sand particles, prevents the "bridging" phenomenon, and ensures the smooth transition of sand particles from the filter bed to the sludge zone.

[0018] 2. This utility model adds a high-pressure water disturbance ring pipe at the bottom of the sludge and sand zone, and uses high-pressure water jet to loosen the bottom sand layer, preventing sand particles from hardening and clogging at the sand lifting zone entrance due to long-term pressure and pollutant accumulation, thus ensuring stable sand lifting by the air lift pump.

[0019] 3. By adding a measuring pole, this utility model enables real-time and intuitive monitoring of the descent speed of the sand bed area. Maintenance personnel can adjust the intensity of air and water disturbance or the operating status of the air lift pump in a timely manner based on the measurement data, turning passive maintenance into proactive early warning, which greatly improves the precision and reliability of operation and maintenance management.

[0020] 4. This utility model has a simple structure and is easy to modify. The combined air and water cleaning method has a synergistic effect, which significantly improves the stability of activated sand filter operation and its ability to resist shock loads, and has good application prospects. Attached Figure Description

[0021] Figure 1 This is a structural diagram of the present utility model; Figure label: 1. Pool body; 11. Clear water zone; 12. Sand bed zone; 13. Sludge and grit zone; 14. Outlet pipe. 2. Sand washer, 21. Sand lifting pipe, 22. Air lift pump, 23. Backwash drain pipe. 3. Water disturbance loop pipe; 31. Spray nozzle; 32. Main water supply pipe; 321. Water supply pipe valve; 33. Water pump. 4. Water distributor; 41. Central riser; 42. Bottom disc-shaped cavity; 421. Water distribution pipe; 43. Water inlet pipe. 5. Radiator fairing 6. Air disturbance ring pipe, 61. Air nozzle, 62. Main intake pipe, 621. Air valve, 63. Angled branch pipe, 7. Sand level drop rate monitoring rod. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] Example like Figure 1The air-water combined sand washing activated sand filter shown includes a tank body 1, which is divided into a clear water zone 11, a sand bed zone 12, and a sludge zone 13 from top to bottom. A sand washer 2 is installed in the center of the clear water zone 11. A backwash drain pipe 23 is connected to the upper part of the side wall of the sand washer 2 and extends out of the tank wall. A sand lifting pipe 21 is arranged coaxially with the sand washer 2, passes through the clear water zone 11 and the sand bed zone 12 in sequence, and extends to the bottom of the sludge zone 13. An air lift pump 22 is installed at its inlet end. The central riser 41 of the water distributor 4 is coaxially sleeved on the outer periphery of the sand lifting pipe 21 and is not connected to it. The top of the central riser 41 is connected to the water inlet pipe 43. The lower end face of the disc-shaped cavity 42 is evenly distributed along the circumference of the vertical water distribution pipe 421, so that the incoming water falls evenly into the sand bed zone 12. The guide hood 5 is a flat-headed truncated cone, with the large end facing downwards to form a sand return port, and the small end closed to allow the sand-lifting pipe 21 to pass vertically through, maintaining a ring-shaped downward channel between the two; multiple air disturbance ring pipes 6 are fixed at equal intervals from top to bottom on the outer conical surface of the hood, and each ring pipe is connected in an airtight manner by two symmetrical oblique branch pipes 63 in sequence. The lower ends of the oblique branch pipes 63 converge and connect to the main air intake pipe 62, which is introduced from the pool wall and equipped with an air valve 621. The air nozzles 61 on each ring pipe are inclined upwards tangentially along the conical surface, with a circumferential interval of 250 mm. The sludge and sand zone 13 is an inverted funnel-shaped cone with a wall inclination angle of 60°, and the small opening is the sand-lifting port; water disturbance ring pipes 3 are arranged on the bottom of the pool around the outer perimeter of the cone, with their spray nozzles 31 pointing vertically upwards, with a ring spacing of 250 mm. The main water supply pipe 32 supplies water through the water pump 33 and the water supply pipe valve 321. The bottom end of the sand level descent rate monitoring rod 7 is inserted into the sand layer of the sand bed zone 12. As the sand particles are continuously lifted away, the sand layer gradually descends, and the monitoring rod moves down synchronously under its own weight, outputting a displacement signal in real time. The upper part of the side wall of the clear water zone 11 is equipped with a water outlet pipe 14 for discharging filtered clear water.

[0029] During operation, wastewater enters the distributor 4 through the inlet pipe 43 and is evenly sprayed onto the sand bed zone 12 through the distribution pipe 421. After filtration, the clean water overflows into the clean water zone 11 and is discharged through the outlet pipe 14. The intercepted sand particles settle to the sludge sand zone 13, and the air lift pump 22 sends the sand particles along the sand lifting pipe 21 into the sand washer 2 for cleaning. The sand washing wastewater is discharged through the backwash drain pipe 23, and the clean sand falls back into the sand bed zone 12 for recycling. Two inclined branch pipes 63 simultaneously supply air to each ring of air disturbance pipes 6. The rotating airflow breaks up the sand particle adhesion and prevents bridging. The water disturbance ring pipe 3 sprays water upward to avoid caking at the sand lifting port. The monitoring rod 7 provides real-time feedback on the sand layer descent speed, enabling active control. The entire system does not require shutdown, and continuous filtration and sand washing are carried out simultaneously, making it suitable for the continuous operation requirements of the deep treatment unit in a wastewater treatment plant.

[0030] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A combined air-water sand washing activated sand filter, comprising a tank body (1), wherein the tank body (1) is provided with a clear water zone (11), a sand bed zone (12), and a sludge zone (13) from top to bottom, and a sand washer (2) is installed in the clear water zone (11), characterized in that: The bottom of the sand washer (2) is connected to a sand lifting pipe (21). The inlet end of the sand lifting pipe (21) extends to the bottom area of ​​the sludge sand zone (13). An air lift pump (22) is installed at the inlet end of the sand lifting pipe (21). A water disturbance ring pipe (3) is installed below the air lift pump (22). A water spray nozzle (31) is provided on the water disturbance ring pipe (3). A water distributor (4) is installed in the sand bed zone (12). A flow guide hood (5) is provided below the water distributor (4). Multiple air disturbance ring pipes (6) are provided on the outer wall of the flow guide hood (5). An air nozzle (61) is provided on the air disturbance ring pipe (6). A water outlet pipe (14) is provided on the outer wall of the clear water zone (11).

2. The air-water combined washing activated sand filter according to claim 1, characterized in that: The water distributor (4) consists of a central riser (41) and a disc-shaped cavity (42) at the bottom. The central riser (41) and the disc-shaped cavity (42) are coaxially sleeved on the outer periphery of the sand lifting pipe (21) and are not connected to each other. The top of the central riser (41) is connected to a water inlet pipe (43). The riser (41) is vertically connected to the cavity (42). Several water distribution pipes (421) are evenly distributed along the circumference of the lower end face of the cavity (42). The axis of each water distribution pipe (421) is vertically downward.

3. The air-water combined washing activated sand filter according to claim 1, characterized in that: The flow guide (5) is a flat-headed truncated cone with its large end facing down and having a sand return port, and its small end facing up and closed; the sand lifting pipe (21) passes vertically through the center of the small end and is coaxially arranged with the flow guide (5), forming an annular sand drop channel between the two.

4. The air-water combined washing activated sand filter according to claim 3, characterized in that: Multiple air disturbance ring pipes (6) are surrounded and fixed on the outer conical surface of the guide shroud (5). Each ring pipe is symmetrically arranged by two oblique branch pipes (63) and connected in an airtight manner. The air nozzles (61) are inclined upward along the tangential direction of the conical surface and are spaced circumferentially.

5. The air-water combined washing activated sand filter according to claim 4, characterized in that: The air inlet ends of the two inclined branch pipes (63) are connected to the main air inlet pipe (62), which is introduced from the side wall of the pool body (1), and its outer air inlet end is used to connect to the main compressed air pipe of the plant area or the outlet of an independent blower.

6. The air-water combined washing activated sand filter according to claim 5, characterized in that: An air valve (621) is provided on the intake manifold (62).

7. The air-water combined washing activated sand filter according to claim 1, characterized in that: The water disturbance ring pipe (3) is connected to a water conveying main pipe (32), the water inlet end of the water conveying main pipe (32) is equipped with a water pump (33), and the water conveying main pipe (32) is equipped with a water conveying valve (321).

8. The air-water combined washing activated sand filter according to claim 1, characterized in that: The upper side wall of the sand washer (2) is provided with a backwash drain pipe (23). The inlet of the backwash drain pipe (23) is connected to the clear water zone (11), and its outlet end extends out of the outer wall of the pool body (1).

9. The air-water combined washing activated sand filter according to claim 1, characterized in that: The pool body (1) is equipped with a sand level drop rate monitoring rod (7), and the bottom end of the sand level drop rate monitoring rod (7) is inserted into the sand bed area (12).

10. The air-water combined washing activated sand filter according to claim 1, characterized in that: The sludge zone (13) is an inverted funnel-shaped cone with its small opening facing down to form a sand-lifting port, and its large opening facing up to connect to the return port of the guide hood (5).

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